msm: ipa: optimizations to enable / disable clocks

Change the way IPA driver maintain the reference count for IPA
clock vote to be based on atomic variables to allow atomic
vote for IPA clocks if clocks are on.

CRs-Fixed: 2079976
Change-Id: If173bd0e21c70a4fb166ea0fb5763d3293c23e8f
Acked-by: Ady Abraham <adya@qti.qualcomm.com>
Signed-off-by: Skylar Chang <chiaweic@codeaurora.org>